Luận văn thạc sĩ: Identify the flood hazard index in the Huong river basin - Hue city area

World Resources InstituteGross Domestic Production Central Committee for Flood and Storm Control Analytical Hierarchy Process Geographical Information System Flood Hazard Index Intematio

I am indebted to my respected Advisors, Dr Pham Thanh Hai and Ass - Prof Hoang Thanh Tung who work as lecturers in Department of Hydrology and Water resources in Thuy Loi University for their continuous guidance, advice and expedience from the proposal preparation to thesis finalization Their constructive comments, untiring help, guidance and practical suggestions inspired me to accomplish this work successfully.

Besides, I am especially grateful to other lecturers in the Department of Hydrology and Water resources who supported me in terms of the data collection and gave me useful advices for my thesis.

I remember all those who have contributed directly or indirectly to successfully completing my study.

Finally, I must express my very profound gratitude to my family for providing

me with unfailing support and continuous encouragement throughout my years of

study and through the process of researching and writing this thesis This accomplishment would not have been possible without them Thank you.

Hanoi, November 11" 2016

Vu Hoang Tung

Thereby declare that is the research work by myself under the supervisions of Dr,Pham Thanh Hai and Assoc Prof Dr Hoang Thanh Tung The results and conclusions

Of the thesis are fidelity, which are not copied from any sources and any forms The

reference documents rel int sources, the thesis has cited and recorded as prescribed,

“The results of my thesis have not been published by me to any courses or any awards

Ha Noi, November 11" 2016

Vu Hoang Tung

Flooding is one of the major natural hazards in the city of Hue This city is frequentlyaffected by flooding and most of the low-lying areas in the city are flood-prone areas,Annually, the losses of people and property caused by flooding in Hue city are very

much This has a great influence on the loeal's life and inhi the socio-economicdevelopment of the city Therefore, in order to minimize losses of life and economic, adetailed and comprehensive flood hazard asses went is necessary for both floodcontrol and mitigation works, The objectives of this research were (i) to simulate floodflow in the city by using 2D hydrodynamic model MIKE 21 FM, (ii) to develop ahierarchical structure through the analytic hierarchy process (AHP) to define andqualify parameters that contribute to flood hazard, (ii) to map the flood componentsusing the geographic information system (GIS), and (iv) to integrate these threemethodologies and apply them to the Huong river basin in the Hue city to create floodhazard index map In addition, based on the sea level rise scenarios for Hue city in

2030, this study also calculated and created flood hazard index maps corresponding to

BI, B2 and AI scenarios Three flood components were considered including flood

depth, flood flows velocity and flood duration Flood maps were thene drawn based on

the data collected from institutes, inheriting the results of studies in the past, anddocuments related to historical flood events, climate change in Hue city The resultsshow that high level of flood hazard tends to broaden over the low, medium and highemission scenarios In the high emission scenario (AI), the high flood hazard zonecovers 45.3% of the study area, While the medium and low hazard zones covers 19.6%and 17.5%, respectively Its concluded that integration of hydrodynamic model, AHPand GIS in flood hazard assessment can provide useful detailed information for floodrisk assessment, and the method can be easily applied to other areas where necessarydata is readily available

World Resources Institute

Gross Domestic Production

Central Committee for Flood and Storm Control

Analytical Hierarchy Process

Geographical Information System

Flood Hazard Index

Intemational Panel on Climate ChangeUnited Nations Framework Convention on Climate Change

Gross Domestic ProductForeign Direct Investment

World Meteorol al Organization

Danish Hydraulic Institute

Digital Elevation Model

‘Community-Based Disaster Risk Management

Asia Disaster Preparedness Center

TABLE OF CONTENTS

CHAPTER I INTRODUCTION 81.1 General introduction, 81.2 Description of the study area 91.3 Deseription of the Huong River 10

1.4 Hue city in the context of climate change "

1.5 Problems and need of study 181.6 Objectives of the study 211.7 Scope of study 21CHAPTER II LITERATURE REVIEW

2.1 Flood hazard mapping 232.2 AHP method 252.3 Flood hazard index 2ï

CHAPTER I METHODOILOGY -:scccssiccserccecrrrecsreeÄ!

3.1 Conceptual framework 303.2 Overview of the research 31

3.3 Flood hazard mapping, 31

3.4 Flood hazard index identification 37

CHAPTER IV DATA COLLECTION AND ANALLYSIS 44'

4.1 Data collection 44.2 Data analysis 4CHAPTER V RESULTS AND DISCUSSION,

5.1 Hydrodynamic model parameters

5.2 Flood hazard mapping 375.3 Flood hazard index 615.4 The impacts of flood on Hue city in the contexts of climate change 625.5 Community-based disaster risk management (CBDRM) m

LIST OF TABLES

‘Table 1.1: Flood season in the Huong river

Table 1.2: The change of average temperature in the recent decades

Table 1.3: Scenario of temperature change in future in Hue

Table 1.4: Scenario of rainfall change in future in Hue city

‘Table 1.5: Scenarios of sea level ris

Table 3.1: Saaty Rating Scale

in the future of Hue city (em)

‘Table 3.2: Random inconsistency indices (RI) for different number ofcriteria

Table 4.1; Pairwise comparison of flood depth categories respect to flood hazard,

‘Table 4.2: Pairwise comparison of flood duration categori

‘Table 4.3: Pairwise comparison of flood velocity categories res

respect to flood hazardpect to flood hazard

‘Table 4.4: Pairwise comparison of components respect to flood hazard

‘Table 5.1: Result of Mike21 FM calibration flood event in 1983

Table 5.2: Hydrodynamic parameters after calibration process

‘Table 5.3: Result of Mike21 FM verification, flood event in 1999

Table 5.4: Flooded area in districts in Hue City

‘Table 5.5: The change of flood depth between climate change scenarios with

Table 5.6: The change of flood hazard levels by area

Table 5.7: What community should do and should not do in each stage of flood

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LIST OF FIGURES

Figure 1.1: Trend of average temperature in July (1986-2006)

Figure 1.2: Trend of average annual temperature in period 1986-2006

Figure 1.3: Trend of average rainfall change in September ~ November

Figure 1.4: Trend of average rainfall change in July

Figure 1.5: The maximum daily rainfall in 10 past decades

Figure 1.6: Administration Map of Thua Thien Hue Province

Figure 2.1: Structure of FHI study methods,

igure 3.1: Framework for flood risk assessment and risk management

Figure 3.2: Overview of the research

Figure 3.3: Study area

Figure 3.4: Steps for model calibration and verifi

Figure 3.5: Diagram for convert

Figure 4.1: Surface topography of the study area

Figure 5.1: Topographic Mesh

Figure 5.2: Checking cross-sections

Figure 5.3: Observed and Calculated discharge at Cross-section 1

igure 5.4: Observed and Calculated discharge at Cross-section 2

Figure 5.5: Observed and Calculated discharge at Cro

Figure 5.6: Observed and Calculated discharge at Cross:

Figure 5.7: Observed and Calculated discharge at Cross:

Figure 5.8: Observed and Calculated discharge at Cross:

Figure 5.9: Flood depth map at the Huong river ~ Hue city in 1999

Figure 5.10: Flood flows velocity map at the Huong river ~ Hue city in 1999

Figure 5.11: Flood duration map at the Huong river Hue city in 1999

Figure 5.12: Flood Hazard Index map at the Huong river ~ Hue city in 1999

Figure 5.13: The change of flood depth in climate change scenarios

Figure 5.14: The change of flood velocity in climate change scenarios

Figure 5.15: The change of flood duration in climate change scenarios

Figure 5.17: Disaster management cycle

ualitative indexes to quantitative value

Figure 3.6: Applying AMP in identifying flood hazard index at the Huong river

igure 5.16: The change of flood hazard index in climate change scenarios

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people at risk of being impacted by river flooding live in three countries: India,

Bangladesh, and China These combined with the next 12 largest impacted populations

~ in Vietnam, Pakistan, Indonesia, Egypt, Myanmar, Afghanistan, Nigeria, Brazil,

‘Thailand, Democratic Republic of Congo, Iraq, and Cambodia - account for 80% ofthe people at risk world-wide In addition, an average of $96 billion in global GrossDomestic Product (GDP) is exposed to river flooding each year And these numbersare expected to increase gradually in the next years because of population growth,

‘urbanization, and climate change As a result, it will increasingly put people at risk

Floods in Viet Nam are well-known phenomena and occur in all regions of thecountry, especially in the Central Coast region (CCFSC 2006) As an example, theCentral Viet Nam’s flood of November 1999 killed 780 people, affected around 1million residents, and sunk and damaged more than 2.100 boats This flood caused

damage worth US§364 million (CCFSC 2006) Being a coastal provinee in Central of

‘Vietnam, Thua Thien Hue province has been suffering from floods impacts annually.Especially, in the context of climate change, catastrophic floo S are in sing in term

of frequency and magnitude, and taking a high death toll, assets and infrastructures

‘Therefore, the measures in flood risk management and mitigation for Thua Thien Hue

province are very indispensable and need to be researched siietly, One of the effective

approaches which are being used widely in flood risk management is flood hazard

as ity to apply in practice and it is a usefulsment This approach showed its cap:tool to facilitate in flood risk management and mitigation

Flood hazard assessment in a river basin can be performed by overlaying maps or/andidentify indexes Each certain area has a hazard value The value can be utilized inanalyzing, estimating and comparing among different areas in order to support for

1g the impacts of floods on Thua Thien Hue province ingeneral and Hue city in particular, this research studies “Identify the flood hazardindex in the Huong river basin ~ Hue city area” The sult of this project will befoundation for identifying the flood risk index and evaluating flood risk in the area,and support to help decision makers in making flood prevention plans for Hue city

1.2 Deseription of the study area

‘Thua Thien Hue is a province in the North Central Coast region of Vietnam The

‘16°15! north, longitudes 107°02' - 108°11

province is located at the latitudes 16°1

cast, Area of the province is 5.053.990 km2; population is 1.115.523 people according

to statistics in 2012 It borders Quang xi province to the North and Da Nang to theSouth, Laos to the West and the East Sea to the East The province has 128 km ofcoastline, 22,000 ha of lagoons and over 200,000 ha of forest The province comprises

4 different zones: a mountainous area, hills, plains and lagoons separated from the sea

by sandbanks The mountains, covering more than half of the total surface of province,with height ranges from 500 to 1480 m The hills are lower, between 20 to 200 m, and

‘occupy about a third of the province's arca, between the mountains and the plains Theplains account for about a tenth of the surface area, with a height of only up to 20mabove sea level Between the hills are the lagoons which occupy the remaining 5% ofthe province's surface area

‘The climate in Thua Thien Hue province is lar to Central Vietnam in general ~ atropical monsoon climate In the plains and in the hills, the average annual temperature

is 25°C, but in the mountains only 21°C (statistical yearbook 2004), The annual

precipitation in the province is 3200 mm but there are important variations Dependingfon the year, the annual average may be 2500 to 3500 mm in the plains and 3000 to

4500 mm in the mountains, In some years the rainfall may be much higher and reachmore than 500 mm in the mountains

“The sale of goods and services in the province is 10930.6 billion VND accounting for0.9% of total sale of goods and services in the whole country This is compared with12.7% of Hanoi and 23.5% of Ho Chi Minh

of coastline, which provides for a seafood industry which produces over 40,000

ity The province has more than 120 km

tons/year consisting of over 500 species of fish

Hue is the city of Thua Thien Hue province The city is the center of culture, polities,

education, science, tourist Area of the city is 71.68 km*, Population in 2012 is

estimated as 344,581 people Hue city is located in downstream of the Huong Riverand Bo River, average height is about 3-4 m above sea level and is often submergedWhen a heavy rain occurs in the upstream of the Huong River

1.3 Deser n of the Huong River

‘The Huong river basin is located from 15°29" ~ 16°35" of the North latitude to

105°07-107°52' of the Bast longitude, with the basin area of 2830 km’ The river

length is 86.5km included 28 distributari The upstream of the Huong River is called

as Ta Trach River which derives from a high mountain area of Bach Ma mountainrange, The Ta Trach River connects with the Huu Trach River at the Tuan confluence.From the Tuan confluence, the main flow is called the Huong River

‘The river then flows in the general direction of southeast to northwest, passing the Huecity, and before flowing into the sea, the Huong River goes through the Tam Giang ~

‘Cau Hai lagoon Tam Giang - Cau Hai is the largest lagoon in the South Bast Asia,With an area of 22,000 ha, and a length of 68 km along the coastline of the provinceFinally, the river flows to the sea at the Thuan An and Tu Hien mouths Besides the

‘Thuan An and Tu Hien estuaries, the lagoon systems have some smaller river mouthslinking to the sea,

same as other rivers in the Central of Vietnam, flood season in the Huong river

bs is not so long, only about 4 months: from September to December with theamount of water accounting for 70% - 75% of total volume of annual flow Therein,November has the largest amount of flood and often account for 30% - 35% of total

‘volume of annual flow Although flood season is short but many large floods occurred

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in the Huong River such as floods happened in 1953, 1975, 1983 and 1999, Thesefloods often lasted in 5-7 days.

‘Table 1.1: Flood season in the Huong river

Station Flood discharge in flood season (m*/s) with P = 75% Average

IX X XI XI discharge

TaTrach | 409 909 204 736 399 Binh Dien | 405 ảo 16s 39.0 286

CoBi “6 836 161 387 34

(Pis flood frequency)

In recent years, many large floods happened in the Huong River According tostatisties, from 1977 to 2005, 34 large flood events which exceeded alarming level IIL

(H > 3m) occurred in the Huong River Observed data at the stations in the Huong

River indicated that there were 4 extreme flood events happened in last 50 years: 1999,

1953, 1975 and 1983 corresponding to 5.81m, 5.50m, 5.32m and 4.92m of water level

In summary, the Huong River plays an important role in development of livelihood,

‘economy and society in Thua Thien Hue province However, the Huong river basin isalso vulnerable and susceptible to natural disaster (especially to flood inundation) andimpacts of climate change In recent years, Thue Thien Hue province and the Huong,river basin has been affected by many natural disasters such as: storm, heavy riflood and drought with high intensity and frequency, caused many losses of people andsocio-economy, damaged cultural heritage and property of local residents

1.4 Hue the context of climate change

LA Climate chang: Hue city

a The change of temperature from the past to now

‘The trend of temperature change is estimated based on series of observed data from

1931 to now Analytic results showed that in this period, the average annual and

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‘monthly temperature has inconsistent change and docs not show a clear trend.

Basically, average annual temperature tends to increase slightly (0.1°C ~ 022°C) from

period 1931 ~ 1940 to 1971 — 1980, however, from the late periods until now,

temperature tends to decrease 0.2°C ~ 0.3°C (Phong, 2014)

Figure 1.1: Trend of average temperature in July (1986-2006)(Source: Climate action plan Responding to Climate Change From 2014 ~ 2020)

Figure 1.2: Trend of average annual temperature in period 1986-2006

(Source: Climate action plan Responding to Climate Change From 2014 ~ 2020)

The scenario for the temperature change in the future

In general trend, average seasonal and annual change is likely to inerease in the future

‘with minimum increase of 1"C in 2050 (corresponding to low emission scenario B1)

‘occurs in the summer The maximum increase of average seasonal and annual

temperature can reach to 3.7°C in 2100 (corresponding to high emission scenario Al).

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‘Thus, the average temperature tends to rise more in the spring and winter while it rise

a litte in the summer In terms of extreme value, the lowest temperature in winter

(corresponding to B2 scenario) increases 1.2°C in 2050 and 2.2°C in 2100, while the

highest temperature increases 2.2°C in 2050 and 3.2°C in 2100 Besides, in 2100, the number of days with maximum temperature above 35°C may increase 10 days —

20days per year (corresponding to medium emission scenario B2) (Phong, 2014)

‘Table 1.2: The change of average temperature in the recent decades

Decades Average temperature in Hue

Average Average | Average annual

temperature in | temperaturein | temperature January July

Seasonal average Extremely temperature (B2)

Winter (XI-I) 14-1.8°C | 1.63.7°C | Minimum: 1.0-1.2°C 2.0-2.2°C

Maximum: 1.2-2.2°C 22-32 Spring) | 12-LớC | 16-37

Summer (VI-VIH) | 10-14% | 1.0-3.1°C Minimum: 1.7-2'C 27-32

B

Maximum: L0-12C

Autumn IXY | 10-16" | 13-3.7%C.

Average annual | 1.2-1.6%C | 1.63.7°C | Minimum: L0-1.7C

Maximum; 1.0-1.7°C | 2,0-3.2°C

+b The change of precipitation from the past to now

According to observed data, annual rainfall in Hue city is relatively high comparedwith other regions with the annual rainfall from 2700 mm to 2800 mm The extremelyhigh total rainfall occurs in some years (for example: rainfall in 1999 was up to 3093mm) Regarding to distribution of rainfall over time, rainfall usually concentratesmainly in October and November In some years, rainfall in one of 2 months accountsfor 60% to 80% annual rainfall (for example the rainfall in November 1999 is 2452

mm while the annual rainfall is 3093 mm)

According to statistics, rainfall in Hue has a considerable variation over the decadesand it does not show a clear trend The average annual rainfall tends to decrease fromthe decade 1961-1970 to 1981-2000(from 2842 mm down to 2575 mm), but thenincrease gradually in the next 2 decades The most si ificant increase is more than

500 mm in 1991-2000 compared with the previous decade Itis worth noting that eventhough the average annual rainfall increases but rainfall in July (dry season) in theperiod 1991-2000-2010 has a strong downtrend, and rainfall in September, Octoberand November (rainy season) tends to increase compared with 2 previous decades

‘Compared with the period 1961-1970, the average rainfall on July in the decade

2001-2010 decreases 23% while the rainfall in November increases 27%

Regarding to rainfall intensity, in the past few decades, the intense rainfalls appearmore and more and always happen in October and November, Heavy rainfall oceurs insome days, for examp! „ on 2" November 1999, a rainfall with 978 mm happened,

accounted for 20% the total rainfall that year

In summary, the average annual rainfall in the decade 2001-2010 is larger than theprevious decades since 1961 but we cannot confirm about the trend of average annual

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value Only one thing we ean confirm is that the rainfall in October and November bayalways reached extremely levels, accompanied by intense rainfalls and tend to rise inOctober and November while the rainfall on July ~ dry season tends to decrease(Phong, 2014)

sao,

Figure 1.3: Trend of average rainfall change in September ~ November

(Source: Climate action plan Responding to Climate Change From 2014 ~ 2020)

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Figure 1.5: The maximum daily rainfall in 10 past decades

(Source; Climate action plan Responding to Climate Change From 2014 ~ 2020) The scenario for the precipitation change in the future

According to forecast, the average annual rainfall in Hue city may increase 3% - 4% in

2050 and 6% - 10% in 2100 The average rainfall in the spring, summer and autumnmay increase while the rainfall in winter may decrease

It is worth noting that the rainfall decreases in the dry season with the maximumdecrease is 6% in the middle and 10% in the end of the decade The rainfall in autumnfrom October to December) has the largest increase with the maximum inerease is up

to 16% in 2100 while the highest rainfall in the year concentrates in this stage As aresult, flood and drought in Hue city is likely to become more serious in the future, Inaddition, the maximum daily rainfall in Hue may increase about 20% compared withcorresponding value in the period 1980-1999 and even the abnormal rainfall canappear with the rainfall rises twice as the record rainfall at present (Phong, 2014)

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Table 1.4: Scenario of rainfall change in future in Hue city,

‘Average annual Increase 3-5% Increase 6-10%

(Source: Climate action plan Responding to Climate Change From 2014 ~ 2020) Sea level rise

Sea level rise scenario for Hue city is taken to the forecasting figures for the regionfrom Ngang mountain pass to Hai Van mountain pass The change of sea level in thefuture is compared with the average sea level in the period 1980-1999,

According to the table below, sea level tends to increase in the future In 2020, 2050and 2100, sea level could rise at the highest level of 9 em, 28 em and 94 em, Besides,the error in forecasting between low emission scenario and high emission scenario

tends to increase over time This shows that the uncertainty of the forecast in future is

larger and larger (Phong, 2014)

‘Table 1.5: Scenarios of sea level rise in the future of Hue city (em)

— Year

emlvdon | 2020 | 2030 | 2040 | 3050 | anao | 2070 | aowo | 2000 | 2100

wt | 74 [mie | toe | 222s | 24A1 | si [iar 4655 | 536

m2 | 89 | as | 179 | 232s re | ara [asst | eer | on

aunt | 89 | 1944 | 1920 | 2628 | 639 | 4651 | 561 | 7099 | 39

(Source: Climate action plan Responding to Climate Change From 2014 ~ 2020)

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1-4.2 The impacts of flood on Hue city in the contexts of climate change

‘The main types of natural disaster in Hue city includes typhoon, flooding, drought,

‘whereas flooding is conside sd as the most dangerous natural disaster and causes the

most damage to Hue In recent years, under the influences of variations regarding

temperature, rainfall floods tend to serious, complicated and unpredictable

Floods usually stly concentrated in the period from

September to December annually Total of flow during flood season accounts forabout 65% of the total annual flow According to observed data, there are 3.5 floods inaverage annually which are equal or higher than flood alarming level IT occurred in theHuong river

Normally, the flood duration is about 3-5 days in average, The longest period of aflood ups to 6-7 days The average time for transferring flood from upstream (ThuongNbat) to downstream (Kim Long) with the distance of $1 km is about 5-6 hours, Theseverity of a flood (flood duration and flood depth) depends on many factors such asrainfall in upstream, rainfall in Hue city, tide and sea level rise (due to storms or the

rising of earth’s temperature)

‘Thus, under the impacts of climate change, in recent decades, floods in Hue city tend

to become more complex, less predictable and more dangerous (Phong, 2014)

1.5 Problems and need of study

Vietnam is a coastal country with a long coastline and located in the tropical monsoonclimate region, Vietnam has suffered impacts of floods annually Since ancient times,Vietnamese people regarded flooding as one of the four biggest dangers to people,along with fires, robbers and invaders

In order to control flooding, a large system of river and coastal dykes hay been

constructed, For many centuries, these flood control measures achieved results all overthe country However, this structure approach is now under pressure because theconditions inducing flooding are intensifying, both at local and global level (CCFSC,2006) For example, increasing population, rapid urbanization, high demand fornatural resource exploitation, environmental pollution, and degradation are coupled

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With global threats, such as climate change (Tran et al 2008) In addition, duc to thelimitation of current fund in Vietnam, non-structure measures are more concentratedand given preference over the structure measures, One of the most effective non-structure measures currently is flood risk assessment Flood risk assessment will be abackground for planning and coping with floods.

Being the central of Thua Thien Hue province, Hue city is located in intersection oftraffic routes from ệ wth to South and East-West economic corridor connecting

‘Thailand, Vietnam and Laos It is also where has interference about society ~ economyculture of 3 regions N North ~ Central ~ South With the importance of a central urban

Where experienced many historical events, Hue city has been had outstanding

development in socio ~ economy, infrastructure, culture, tourism In recent years,infrastructure, new urban areas have been invested continuously and this made theappearance of Hue city become more modern and civilized

In the context of climate change, Thua Thien Hue province in general and Hue city in

particular is suffering from many impacts of climate change, The ultra-weather events

tend to become more severe in terms of both frequency and magnitude The directconsequences caused by climate change in Hue city in recent years ate the occurrence

‘of many events such as flood, storm, drought and deep freeze These events haveinfluences on social and economic development Whereas, flooding is considered as atop threat to coastal cities like city of Hue This was demonstrated via the historicalflood events, such as the flood events in 1953, 1975, 1983, 1999 And now, thesevere flood events are still happening more and more powerful under the impacts ofclimate change

‘The flood event started from 20 to 26/9/1953 caused 500 casualties, swept away 1290houses, 80% of the crops were lost

A big flood occurred from 15-20/10/1975 took a heavy toll of people and property

“The flood event in 1983 lasted for 8 days with the flood peak discharge observed at Co

Bi, Binh Dien and Thuong Nhat station corresponding to 2850 mÏ/4, 4020 m'/s and

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1470 m'/s, The flood caused 252 dead, 115 people were wounded, 2100 houses were

collapsed, and 1511 houses were swept away

The flood event 11/1999 happened for 6 days (1/11 ~ 6/11), was a very large flood

“The flood peak discharge observed at Ta Trach, Binh Dien and Co Bi stations

100-6000 mÏ/4 and 3500-4000 m'¥s The flood

corresponding to 7000-8000 ms, 5

caused widespread inundation and flood damage was enormous Flood level in the

‘upstream up to 1.4 m, more than 90% residential areas living in the delta weresubmerged for 4-9 days From 1/11 to 12/11, there were 372 dead and missing, totaldamage was estimated as 1,762 billion VND Transportation sector had the most

‘damage of 600 billion VND, followed by Agriculture sector of 307 billion VND andFishery sector of 110 billion VND

According to predictions of experts, Hue city will be one of areas where has to suffer

from many impacts of climate change in the process of socio-economic development.Vulnerability caused by climate change to Hue city is considered more serious than

‘other regions in the province due to population density and the level of infrastructureinvestment is very high, especially, Hue city is planning to become a nuclear urban inthe future, However, the problems related to climate change are still new and have notbeen perceived deeply and implemented specifically to local authorities and residents.Although, the local authority has made great efforts in urban management,environmental protection and disaster damage mitigation, but the role of the cityauthority in adaptation and mitigation of climate change impacts is not clear Facing

with negative effects of climate change requires the local authority need to assess

properly the situation and existing capacity in responding, then recommends suitablesolutions to minimize the negative impacts caused by climate change,

Facing with the problems as mentioned above, this study will identify one of the mostimportant components in Flood risk assessment in the Huong river basin: Flood hazardindex Flood hazard index represents the level of flooding impacts, tis combination ofall hazard parameters such as flood depth, flood duration, velocity of flood flow

Base on the index, the hazard zones are determined The impacts of flood on local

people, social-economic development in whole study area can be reduced by the

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siructure and non-structure measures, However, the structure and non-strueturemeasures also need detailed calculations and estimations in order to mitigate theinfluences of flood in the economical and efficient way.

1.6 Objectives of the study

The ger

in the Hue city

ral objective of this study is to support to flood control and mitigation works

‘The specific objectives of the study are:

1 Simulate flood flow: Simulation and estimation magnitudes, drainage process, andAlooding flow along the river

2 Create flooding maps: Developing flood depth, flood velocity, flood duration mapsfor the river bas

3 Identify flood hazard index: quantify factors which contribute to the damagingpotential of flood hazard to serve for flood tisk assessment,

~ Selecting suitable model for simulating flood processes in the Huong River

Calibrating and verifying the selected model

= Developing flood hazard mapping based on results of the above model and analysis

- Applying Analytical Hierarchy Process (AHP) method and ArcGIS software todevelop flood hazard maps and calculate flood hazard index

~ Assuming scenarios in context of climate change to estimate the impacts of flood toHue City in the future

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~ Recommending some non-structure measures to help local residents in coping with

flooding.

CHAPTER II LITERATURE REVIEW

Flood hazard assessment including the integration of GIS and hydraulic model as well

as identitying indexes related to flooding by applying weight methods have beendescribed and studied by many researchers Thes approaches are also estimated aseffective approaches in flood hazard assessment currently In order to determinetheoretical base for this research, some available references have been reviewed, Thischapter summarizes the review of related literature as following structure:

Literaturereview

AHP method

lood hazard index

Figure 2.1: Structure of FHI study methods

2.1 Flood hazard mapping

Gardiner (1990), as cited by Omran et al (2011), indicated that, the morphomeiccharacteristics of basins have been used to predict and describe flood peaks andestimation of erosion rate Indeed, the relationship between basin morphometric andflooding impact have also been investigated Morphometric studies include theevaluation of streams through measurement of stream network properties, which are

2B

ealeulated based on such character ies as drainage density, water allocation ratio,

s difficult to measure the details ofstream frequency and overland flow However,

drainage elements in the field due to their extent throughout rough terrain over vastarea, Thus, in order to solve the task, the author applied GIS techniques to extract thestream networks as well as analysis morphologic characteristics of the basin The aim

of this research is to produce a potential flood hazard map based on geomorphicparameters and to estimate the risk degree of individual sub-basin in the study area

According to Marfai and Njagih (2002), flood is recognized as one of two hazardousphenomenon which has the most serious damages to people and economy in Turialba

City in Costa Rica annually Therefore, the authors found that it's necessary to do tiskassessment in order to know how much would be the damage if the flood hazard

‘occurs, In the research, the authors considered flood hazard assessment as anindispensable part in flood risk assessment, beside flood vulnerable assessment In thispart, he used ILWIS software to generate the flood hazard maps corresponding tovarious retum periods These maps then were used to serve for risk assessment andcost estimation for study area,

Karagiozi er al (2011) conducted their research in Laconia Prefecture in Peloponneus,Greece In the research, flood hazard assessment was implemented by usinghydrological models in a GIS environment taking into account the geomorphologiccharacteristics of the study area For each basin, the morphologic characteristics such

4 area, mean slope, mean elevation and total relief were calculated These factors then

‘were combined by using GIS to produce a final flood hazard map,

According to Ripendra (2000), flood hazard mapping and risk assessment in Nepal isstill rudimentary Most of the flood protection works were carried out at the local scalewithout proper planning or without considering the problem at river basin scale, Apartfrom piecemeal approaches on a limited scale, no pragmatic efforts in comprehensivefood risk assessment and flood hazard mapping have been done, Therefore, in his ownstudy, he prepared flood vulnerabil ty, flood hazard and flood risk maps by integratingthe hydraulic model HEC RAS and GIS with the case study of Lakhandei River basin

“The results of the research are the flood vulnerability, flood hazard and flood risk

4

maps with the assessment for cách elements, The author then emphasized to theimportant role of community as well as stakeholders in flood management and madethe action plan for flood mitigation in study area,

2.2 AHP method

Siddayao et al (014) combined Analytical Hierarchy Process (AHP) method withGeographical Information System (GIS) for flood risk analysis and evaluation in thetown of Enrile, a flood-prone area located in northern Philippines AHP resultsshowed the rela ive weights of three identified flood risk factors, and these results

ng the GIS

‘were validated to be consistent, using @ standard consistency index Us

software, the factor weights from the AHP were incorporated to produce a map with 5

levels of estimated flood risks Using such a TIS weighted overlay analysis map as

‘guide, local residents and other stakeholders can act to prepare for potential flooding,promote appropriate land-use policy that will minimize threat to lives due to flooding

According to Chen ef al, (2011), flooding is one of the major natural hazards inTaiwan and most of the low-lying areas in Taiwan are flood prone areas Thus, acomprehensive decision making tool for flood control planning and emergency service

‘operation is necessary in order to reduce losses of life and economy A research aboutflood risk assessment was then carried out by him The research objectives were todevelop a hierarchical structure through the Analytic Hierarchy Process (AHP) toprovide preferred options for flood risk analysis; map the relative flood risk using theGeographic Information System (GIS), and integrate these twvo methodologies in floodrisk assessment The results of research indicated that integration of AHP and GIS in

flood risk assessment can provide useful detailed information for flood risk

management, and the method can be easily applied to most areas in Taiwan whererequired data sets are readily aval

‘A flood hazard assessment using AHP and mapped by GIS has also been applied forthe Yasooj River, Iran (Rahmati er al 2015) The aim of this research is to identify

potential flood hazard zones The decision factors for flood hazard of the AHP matrix

include distance to river, land ws elevation and land slope The set of criteria wereintegrated by weighted linear combination method using ArcGIS 10.2 software to

25

‘generate flood hazard prediction map, The efficiency of AHP method in identifyingpotential flood hazard zones was then accessed by comparing with the results of thehydraulic model HEC-RAS Finally, the results showed that the AHP technique ispromising of making accurate and reliable prediction for flood extent, Therefore, theAHP and geographic information system (GIS) techniques are suggested forssment of the flood hazard potential, specifically in un-gauged regions,

The integration between AHP and GIS was also applied in flood hazard assessment inKujikuri Plain, Chiba Prefecture, Japan (H Chen et al 2014) In the research, sixfactors were selected includi ig river system, elevation, depression area, ratio of

impermeable area, detention ponds, and precipitation, The method of analytic

hierarchy process was applied to calculate the weighting values of cach factor Theflood hazard map was also obtained The hazard map was then compared with theactual flood area, and good coincidence was found between them In conclusion, theflood hazard assessment method presented in the research is meaningful for the floodmanagement and environment protection in the area under the similar condition as thisstudy

Aji et al (2013) conducted flood hazard a ssment in Ghaggar basi India by using

‘Multi criteria evaluation methods In the research, the authors showed some criteriawhich are characteristics of study area and have the strongest effect in triggering

flood in the area The maps of Rainfall distribution, micro watershed size, slopedrainage density, soil type, land use land cover, and Roads/micro watershed werecreated using Equal Interval Method in ArcGIS software by assigning weightage forcach class The final result of this research is the Flood hazard zone map with floodprone areas was identified after the author gives suitable rank for each contributingfactors based on its estimated significance in causing flood

Until now, many studies applied advanced technologies such as the integrationbetween GIS and hydrodynamic models in order to analysis and assess flood hazardvery well However, most of studies used the ID hydrodynamic models In order to

make the assessment results more accurate, the combination between GIS tools and 2D

model should be applied in researches,

6

2.3 Flood hazard index

Flood hazand assessment is considered as an essential part in the flood risk assessmentfor Phrae flood plain of the Yom River basin in northern Thailand by Tingsanchali andKarim (2010) The study was carried out by applying a hydrologie-hydrodynamicmodel in association with a geographic information system (GIS) Flooding scenarioswere estimated in term of flooding depths for 25, 50, 100, 200 years return periods

‘The authors then select critical depths based on the guide-lines in the flood-plaindevelopment manual to create four hazard categories A hazard index was introduced

in the research to represent degree of hazard corresponding to each category Theresults showed that 78% of the Phrae flood-plain area of 476 km2 in the upper YomRiver basin lies in the hazard zone ofthe 100 years return period flood

‘Masood (2011) carried out flood hazard assessment for the mid-eastem Dhaka,Bangladesh In the research, the inundation simulation is conducted by using HBC-RAS model for 100 years flood A Flood Hazard map then was prepared using theinundation status which was found from hydrologic simulation Based on theinundation depth, the hazard index was assigned for the study area The index then wasassociated with vulnerable index to calculate flood risk index with the purpose ofassessing flood risk for the area,

‘According to Elkhrachy (2015), flash flood in the cities led to high levels of water inthe streets and roads, causing many problems such as bridge collapse, building damageand traffic problems It is impossible to avoid flood risk or prevent flood occurrence,bur it is plausible to reduce their effects and the losses The author supposed that flashflood mapping to identify sites in high risk flood zones is one of the powerful tools forthis purpose Therefore, the objective of this paper is to generate flash flood map forNajean city, Saudi Arabia, using satellite images and GIS tools AnalyticalHicrarchi ht of floodI Process (AHP) is also used to determine relative impact wcausative factors to get a composite flood hazard index (FHI) The causative factors in

this study are runoff, soil type, surface slope, surface roughness, drainage density,

distance to main channel and land use

27

Flood hazard mapping is also considered as a vital component for appropriate land useplanning in flood-prone areas (Bapalu, 2006) The research was carried out to identifyflood hazard index for Kosi river basin, North Bihar, India in a GIS environment Theauthors used one of the multi-criteria decision-making techniques, AnalyticalHierarchical Process (AHP) which provi ides a systematic approach for assessing andintegrating the impact of various factors A composite index of flood hazard derivedfrom topographical, land cover, geomorphic and population related data All data arefinally integrated in a GIS environment (© prepare a final Flood Hazard map Thisflood hazard index computed from AHP method not only considers susceptibility ofcach area to be inundated but also takes into account the factors that are inherentlyrelated to flood emergency management,

“The role of flood hazard map is emphasized one mote time in the research of Forkuo(2011) because ofits advantages such as easily read and rapidly accessible This studyaddresses the need for an efficient and cost-effective methodology for preparingflood hazard maps in Ghana A composite flood hazard index of the study area wascreated by incorporating variables of near distance to the White Volta River,

population density, number of towns in each district, area of cultivated savanna

(crops), and availability of high ground (Shelter) Also, maximum flood hazardzones were mapped in a GIS environment

Conclusion:

‘The references mentioned above at first indicated the necessary of flood hazardassessment while flood has strong impacts on people, socio-economy in regions otareas where could be affected easily by flood There are many approaches ormethodology employed to do this assessment However, one of the methodologiesapplied widely in flood hazard assessment nowadays iš the integration ofhydrodynamic models and Geographical information system This methodologydemonstrated its capabilites and applicability in flood hazard assessment viareferences mentioned above Therefore, this research will use a hydrodynamic model

factors of a flood by

to simulate the flooding process and then show the speci

creating visual maps in GIS environment

28

Besides flood simulation and flood map creation, flood hazard index identification alsohhas a great significance in flood hazard assessment Flood hazard index is determinedbased on the factors related to flood and the weight of each factors AnalyticalHierarchy Process (AHP) method applied in references mentioned above is a powerfultool in group deci making and it is used to quantify the qualitative preferencesamong components or subcomponents as well as indicators or categories Thus, the

itor, andresearch will applied this method to assess the importance of each flood fa

then identify the flood hazard index in GIS environment

‘The integration of GIS and AHP method has been applied in many researches

regarding flood hazard assessment and flood hazard identification In some researches

mentioned in literature review, the components of a flood are selected based on thetopographic and geomorphological characteristics However, the collection of thesedata is very difficult in reality due to the limitations of system of measurements in

ied based on floodVietnam In other researches, flood hazard index was just ident

depth, Flood depth

impacts on people and socio-e

critical component of a flood when we consider to the flood

‘onomy But, if only this component is considered inidentifying flood hazard, itis unable to ac

‘Therefore, thi

23s comprehensively the flood influences.

study will select 3 crucial components of a flood: flood depth, floodduration and flood velocity and used them as 3 criterions in flood hazard assessmentand flood hazard index identification,

In addition, the reports and documents of international organizations and Vietnam.agencies indicated that flood properties will tend to increase significantly under theeffects of climate change in the future in Central of Vietnam in general and city of Hue

in particular Thus, this study will base on the climate change scenarios which built forHue city to identify flood hazard index for this area in 2030 Finally, the study willhave comparisons between the historical floods with the flood which is predicted inthe future for the purpose of assessing the changes of flood by time,

2»

CHAPTER II METHODOLOGY 3.1 Conceptual framework.

‘rst Es Map

a >

Risk Asesment

isk anton zal Valeriy, Value)

Planning Mignon Measures

Redace Risk Toagh Bex Posie

‘Managemen Practices

> Land we Plating (Food Pin Maine)

> Seufl Mess (Dans, BalMzCols)

Pod Forcing and Waning Ses

Protection Goal Rik Acceptance

—

—-Implementation

‘and

———— Periodic Review

Figure 3.1: Framework for flood risk assessment and risk management

‘Source: Adapted from WMO, 1999

In the Flood risk assessment and flood risk management, flood hazard assessment

plays an important role, This research focuses on the assessment and quantification of

the indicators of flood hazard,

Flood risk assessments starts with an assessment of the flood hazard, which indicates

the probability and intensity of a possible event (de Moel et al, 2015) Flood hazard

30

could be estimated through many indicators, however, three basis characteristics areflood depth, flood velocity, flood duration The flood depth and flood velocity havedirect impacts on infrastructure, houses, loss of life, public health, Flood durationcauses indirect and intangible damages such as diseases, life disruption stress This

research will base on these Factors to quantify and idemtiy hazard index in the Huong

Hydraulic model (MIKE 21)

Simulating and estimating flood

inundation process

Study area

Data analysis

GIS tools (MIKE-21, AreGIS)

Estimating the depth, duration andvelocity ofthe flood,

(Quantify the factors and IdentifyFlood Hazard index

Figure 3.2: Overview of the researeh,

3.3 Flood hazard mapping

Flood hazard mapping is the basic document, the scientific basis for flood preventionplanning, selection of measures, design of flood control constructions and the

31

necessary information to inform to people about the potential damage caused by flood

in local areas

Flood hazard mapping determines the boundaries of inundation areas caused by aflood event The boundary of an inundation area relies on flood water level,topographic and geomorphologic factors in the area; while topographic factors havefewer changes, flooding boundary depends on variations of flood water level,

There are 3 approaches are being applied in creating flood hazard maps:

~ Traditional approach: Creating flood hazard maps based on geomorphological

survey,

~ Creating flood hazard maps based on big flood events which oceurred inhistory

~ Creating flood hazard maps based on hydraulic and hydrologic models,

Each approach has its advantages and disadvantages in generating and estimatingflooding areas Flood hazard maps which are built by traditional approach, onlyreproduce flooding status 1s unpredictable but it still has great significance incommanding flood prevention as well as being the basis in evaluating and comparing

further studies However, this approach takes a long time, has low predictability and

does not meet the actual needs,

Generating flood hazard maps based on survey data and the data of flood events which

‘occurred in the past is the most reliable, However, the data for major flood events isinadequate and unpredictable in the future Thus, this approach limits many

advantages and applicability of flood hazard maps in practice

Applying hydrologic and hydraulic models is an effective way in simulating theflooding Besides, this is also a moder approach and being used widely in the world

as well as in Vietnam, Otherwise, with the fast-paced development of computer,information system and database, an increasing number of applications developedbased on geographic information system (GIS), in which, creating flood hazard maps

32

is one of important application, which brings practical benefits in flood prevention anddisaster mitigation,

‘Therefore, this thesis will focus on calculating and analyzing inundation process byapplying hydrodynamic model The outputs of the model then will be used for creatingflood hazard map in GIS environment

3.3.1 Application of 2D hydrodynamic model - MIKE 21 Flow EM in floodsimulation

3.3.1.1 Hydrodynamic model ~ MIKE 2IEM

MIKE 21 Flow Model EM is a two-dimensional hydraulic model of the MIKEsoftware The model has been built and developed by the Danish Hydraulic Institute

(DID since the late 90s Mike 21FM model was presented in Vietnam in November

2005 by technology transfer between DHI and Irrigation Planning Institute MIKE 21

is dedicated software which is used to simulate the 2 dimensional variations of waterlevel and flow in lake, estuary, bays, coastal and offshore areas

MIKE 21 Flow Model FM was built and incorporated with new model techniques andwses unstructured mesh approach (triangular mesh) This technique has been

de oped for applications related to environment in estuary, coastal areas, oceans and.inland flood overflow

MIKE 21 Flow Model FM is composed of following modules:

~ Hydrodynamic module

~ Transport module

= Beo LabvOil spill module

~ Particle tacking module

~ Mud Transport module

3

Hydrodynamic module is the basic computational component of the entire MIKE 21Flow model FM modeling system providing the hydro-dynamic basis for the ‘Transportmodule, Eco Lab/Oil spill module, Particle tracking module, Mud Transport moduleand Sand Transport module.

With the advantages in creating a flexible mesh, the scientific basis of MIKE 21 FM

showed the applicability with following researches:

= Studying overall bydraulic regime across the river and details at each location

including characteristics of water level, discharge, flow velocity and their horizontaldistribution, Especially, the model has a great performance in calculating the flow inthe rivers which have many changes about direetion of flow — an important component

in the study of erosion and accretion

~ Calculating the changes of river bed and erosion river banks in its natural status as

well as plans of exploitation in the river in the future

3.3.1.2 Study area

‘The study area is the Huong river section ~ Hue city with the length of 10 km

3

3.3.1.3 2D MIKE 21 EM calibration and verification

The model calibration is primarily conducted by modifying the value of Bedresistance The method is used for model calibration in the study is trial-error method

Assume the Run the Good Select

parameters model > assumed

parameters

Bad

Modify the

parameters

Figure 3.4: Steps for model calibration and verification

‘The concrete steps are described as below:

= Select an observed data series which is adequate and reliable for model

calibration

Set up parameters for model calibration

~ Identify the riteria to evaluate the error for calibration process

Use trial-error method to find out the parameters satisfying the give erteria

= After the suitable parameters for calibration is found out, the parameters areused for model verification with a different observed data series

‘The result of the model is evaluated by criteria for error assessment:

= The difference between the peak of observed flood data and calculated flooddata:

Whereas: Hy": Value of calculated peak of water level

Hy": Value of observed peak of water level

~The Nash ~ Sutcliffe model efficiency coefficient:

35

© (ai-Hsi2

Whereas: Ho: Value of observed water level

á: Value of water level which is calculation in Mike 21 FM.

3.3.2 Flood Hazard mapping

3.3.2.1 Overview of ArcGIS

AreGIS (ESRI Ine, - http:/vww.esri com): is the state of the art GIS system, provides

4 comprehensive solution from collecting, revising, analyzing data and distributinginformation on the Internet to different levels as personal geographic database and

‘business database In term of technology, GIS professionals consider ESRI technology

as an open and completed solution which has capacity in exploiting all functions ofGAS in various applications such as: desktop (ArcGIS Desktop), Server (ArcGIS

dd Web applications (ArcIMS, Are

server)

(ArePAD)

IS online), or mobile system

AroGIS Desktop (with the newest version as ArcGIS 10) consists of powerful tools in

managing, updating, analyzing information and creating a complete geographic

information system, allows:

allows using different data formats, even the data which is downloaded from the

| data integrated with attribute data) —

Internet

~ Querying spatial data and attribute data from many sources and in many different

ways,

~ Displaying, querying and analyzing spatial data in combination with attribute data

- Establishing thematic maps and professional-quality pre: entation,

In case of associating with hydrologic and hydraulic models, AreGIS is ănindispensable component, The role of GIS tools is presented in

36

~ Synthesizing and selecting documents as important inputs in hydrologic andhydraulic models.

~ Analyzing, visualizing and assessing the area and the levels of inundation using the

‘outputs of above models

3.3.2.2 Flood hazard mapping

Flood hazard map can be assessed through basic indicators such as flood depth, floodduration, flood velocity debris in the flood flow (sediments, salts, chemicalsubstances, waste water and soil).cte In the elements mentioned above, flood depth,food velocity and flood duration play an important role in identifying flood damage,

‘The integration between flood depth and flood velocity demonstrates the ability to

destroy objects in affected areas It a direct impact on the objects such as houses,

buildings, people lives Flood duration has an indirect effect on socio-economicactivities, environmental pollution, diseases, community's health Based on the mapoverlaying method to overlay flood depth, flood velocity and flood duration maps (he

‘outputs of MIKE 21), the study will build the flood hazard map for flood event in1999

3.4 Flood hazard index identification

3.4.1 Analytical Hierarchy Process (AHP)

AHP method is a pairwise comparison method which has the added advantages ofproviding an organized structure for group discussion, and helping the decisionmaking group focus on areas of agreement and disagreement when setting criterion

‘weights (Drobne & Lisee, 2009)

“The technique of pairwise comparisons has been developed by Saaty in 1977 in thecontext of a decision making process known as the Analytical Hierarchy Process(AHP), In Saatys technique, weights of this nature can be derived by taking theprincipal eigenvector of a square reciprocal matrix of pair-wise comparisonsbetween the criteria The comparisons deal with the relative importance of thetwo criteria involved in determining suitability for the stated objective Ratingsare provided on a nine-point continuous scale (Table 3.1)

3?

Table 3.1: Saaty Rating Scale

: tealmpeneee —- Teefeamnnvbdrsaelriotedteke

2 TT" ance no hay ron hr

Nhe spec i gn gyi ee

7 ‘Scab Ee ey sermons is

h NT TH YớYnn

Source:(Haryanto, 2014)

In developing weights, an individual or group compares every possible pairing and

centers the ratings into a pairwise comparison matrix or ratio matrix Since the matrix is

symmetrical, only the lower triangle actually needs to be filled in The remaining cellsare then simply the reciprocals of the lower triangle (Drobne & Lisec, 2009)

‘The procedure then requires that the principal cigenvector of the pairwise comparison

‘matrix must be computed to produce the best fit set of weights A good approximation

to this result can be achieved by following the operations below: (Drobne & Lisec,

2009)

~ Sum the values in each column of the pairwise comparison matrix;

- Divide each element in the matrix by its column total (the resulting matrix is referred4o as the normalized pairwise comparison matrix); and

~ Compute the average of the elements in each row of the normalized matrix, that is,divide the sum of normalized scores for each row by the number of criteria,

‘These averages provide an estimate of the relative weights of the relevant criteria,Here, the weights are interpreted as the average of all possible ways of comparing the

criteria

In practice, it is not always possible to build transitive relation during pair-wisecomparisons For example, the plan A may be better than B, B may be better than C,

38

bút A may not be better than C This called inconsistency The inconsistency is realbut inconsistency level should not be too high because it shows the incorrectassessment then, AHP provides mathematical measures to determine the inconsistencylevel of judgments through the consistency ratio (CR) Ifthe value is les than or equal40.0410, itis acceptable Otherwise, if this value is greater than 0.10, it is necessary toTe-assess the previous steps.

Estimation of the consistency ratio involves the following operations: (Drobne &Lisee, 2009)

- Determination of the weighted sum vector by multiplying the weight for the first

criterion times the first column of the original pairwise compat son matrix, then

multiplying the second weight times the second column, the third criterion times thethird column of the original pairwise matrix, and so on to the last weight, and finallysumming these values over the rows; and

Determination of the consistency vector by dividing the weighted sum vector by thecriterion weights determined previously

‘The consistency ratio is defined as:

criteria

“The random index is the consistency index of the randomly generated pairwisecomparison matrix and depends on the number of elements being compared Table 3.2shows random inconsistency indices (RI) for different numbers of criteria,

39

Table 3.2: Random inconsistency indices (RD) for different number of criteria

Tapa Pines comparison xe